<template>
  <div class="banner">
    <div class="item">
      <img :src="dataList[currentIndex]" />
    </div>
    <div class="page" v-if="this.dataList.length > 1">
      <ul>
        <li @click="gotoPage(prevIndex)">&lt;</li>
        <li
          v-for="(item, index) in dataList"
          :key="index"
          @click="gotoPage(index)"
          :class="{ current: currentIndex == index }"
        >
          {{ index + 1 }}
        </li>
        <li @click="gotoPage(nextIndex)">&gt;</li>
      </ul>
    </div>
  </div>
</template>

<script>
export default {
  name: "Home",
  data: function() {
    return {
      dataList: [
        "https://i1.mifile.cn/a4/xmad_15535933141925_ulkYv.jpg",
        "https://i1.mifile.cn/a4/xmad_15532384207972_iJXSx.jpg",
        "https://i1.mifile.cn/a4/xmad_15517939170939_oiXCK.jpg"
      ],
      currentIndex: 0, //默认显示图片
      timer: null //定时器
    };
  },
  methods: {
    gotoPage(index) {
      this.currentIndex = index;
    },
    //定时器
    runInv() {
      this.timer = setInterval(() => {
        this.gotoPage(this.nextIndex);
      }, 8000);
    }
  },

  mounted() {
    this.runInv();
  },
  beforeDestroy() {
    clearInterval(this.timer);
  },
  computed: {
    //上一张
    prevIndex() {
      if (this.currentIndex == 0) {
        return this.dataList.length - 1;
      } else {
        return this.currentIndex - 1;
      }
    },
    //下一张
    nextIndex() {
      if (this.currentIndex == this.dataList.length - 1) {
        return 0;
      } else {
        return this.currentIndex + 1;
      }
    }
  }
};
</script>

<style lang="stylus" scoped>
* {
        margin: 0;
        padding: 0;
    }
    ul li {
        list-style: none;
        float: left;
        width: 30px;
        height: 40px;
        line-height: 40px;
        text-align: center;
        cursor: pointer;
        color: rgba(255,255,255,.8);
        font-size: 14px;
    }
    .banner {
        max-width: 90%;
        margin: 0 auto;
        position: relative;
        margin-top: 10px;
    }
    .banner img {
        width: 100%;
        display: block;
    }
    .banner .page {
        background: rgba(0,0,0,.5);
        position: absolute;
        right: 0;
        bottom: 0;
        width: 100%;
    }
    .banner .page ul {
        float: right;
    }
    .current {
        color: #ff6700;
    }
</style>
